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39 >Privoxy Frequently Asked Questions</TH
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82 >4.1. How much does <SPAN
85 > slow my browsing down? This
86 has to add extra time to browsing.</A
89 > It should not slow you down any in real terms, and may actually help
90 speed things up since ads, banners and other junk are not being displayed.
91 The actual processing time required by <SPAN
95 itself for each page, is relatively small in the overall scheme of things,
96 and happens very quickly. This is typically more than offset by time saved
97 not downloading and rendering ad images.</P
106 mechanism may cause a perceived slowdown, since the entire page is buffered
107 before displaying. See below.</P
115 >4.2. I noticed considerable
116 delays in page requests compared to the old Junkbuster. What's wrong?</A
119 >Using the default filtering configuration, I noticed considerable delays in
120 page requests compared to the old Junkbuster. Loading pages with large contents
121 seemed to take forever, then suddenly delivering all the content at once.
124 >The whole content must be loaded in order to filter, and nothing is is
125 sent to the browser during this time. The loading time does not really
126 change in real numbers, but the feeling is different, because most
127 browsers are able to start rendering incomplete content, giving the
128 user a feeling of "it works".
131 >To modify the content of a page (i.e. make frames resizeable again, etc.) and
132 not just replace ads, <SPAN
135 > needs to download the
136 entire page first, do its content magic and then send the page to the browser.</P
144 >4.3. What is the "http://p.p/"?</A
150 > sits between your web browser and the Internet, it can be
151 programmed to handle certain pages specially.</P
153 > With recent versions of <SPAN
157 greater), you can get some information about
161 > and change some settings by going to
166 > or, equivalently, <A
167 HREF="http://config.privoxy.org/"
169 >http://config.privoxy.org/</A
171 that p.p is far easier to type but may not work in some configurations. With
172 the name change to <SPAN
175 >, this is changed from
176 the previous http://i.j.b/ and earlier 2.9.x versions).</P
181 > forwarded to a server on the
182 Internet - instead they are handled by a special web server which is built in to
188 > If you are not running <SPAN
196 HREF="http://config.privoxy.org/"
198 >http://config.privoxy.org/</A
200 return a web page telling you you're not running
206 > If you have version 2.0.2, then the equivalent is
207 http://example.com/show-proxy-args (but you get far less information, and
208 you should really consider upgrading to 2.9.14).</P
216 >4.4. Do you still maintain the blocklists?</A
219 > No, not by this name. The format of the blocklists has changed
220 significantly in versions 2.9.x and later. This functionality
224 > file now. See next question ...</P
232 >4.5. How can I submit new ads?</A
235 > Beginning with <SPAN
237 >Privoxy v2.9.14</SPAN
239 banners and other actions file problems, can be submitted by accessing
241 HREF="javascript:w=Math.floor(screen.width/2);h=Math.floor(screen.height*0.9);void(window.open('http://www.privoxy.org/actions','Feedback','screenx='+w+',width='+w+',height='+h+',scrollbars=yes,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());"
245 >"actions file feedback system"</SPAN
254 > This process does not work with earlier versions of <SPAN
264 There will soon be regularly updated actions files posted. These
265 will be announced on the
267 HREF="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce"
279 >4.6. How can I hide my IP address?</A
282 > You cannot hide your IP address with <SPAN
285 > or any other software, since
286 the server needs to know your IP address to send the answers back to you.</P
288 >Fortunately there are many publicly usable anonymous proxies out there, which
289 solve the problem by providing a further level of indirection between you and
290 the web server, shared by many people and thus letting your requests "drown"
291 in white noise of unrelated requests as far as user tracking is concerned.</P
293 >Most of them will, however, log your IP address and make it available to the
294 authorities in case you abuse that anonymity for criminal purposes. In fact
295 you can't even rule out that some of them only exist to *collect* information
296 on (those suspicious) people with a more than average preference for privacy.</P
298 >You can find a list of anonymous public proxies at <A
299 HREF="http://www.multiproxy.org/anon_list.htm"
303 more through Google.</P
314 > guarantee I am anonymous?</A
317 > No. Your chances of remaining anonymous are greatly improved, but unless you
318 are an expert on Internet security it would be safest to assume that
319 everything you do on the Web can be traced back to you.</P
324 > can remove various information about you,
328 > more freedom to decide which sites
329 you can trust, and what details you want to reveal. But it's still possible
330 that web sites can find out who you are. Here's one way this can happen.</P
332 > A few browsers disclose the user's email address in certain situations, such
333 as when transferring a file by FTP. <SPAN
337 does not filter FTP. If you need this feature, or are concerned about the
338 mail handler of your browser disclosing your email address, you might
339 consider products such as <SPAN
344 > Browsers available only as binaries could use non-standard headers to give
345 out any information they can have access to: see the manufacturer's license
346 agreement. It's impossible to anticipate and prevent every breach of privacy
347 that might occur. The professionally paranoid prefer browsers available as
348 source code, because anticipating their behavior is easier. Trust the source,
357 >4.8. Might some things break because header information is
361 > Definitely. More and more sites use HTTP header content to decide what to
362 display and how to display it. There is many ways that this can be handled,
363 so having hard and fast rules, is tricky.</P
368 > in particular is often used in this way to identify
369 the browser, and adjust content accordingly. Changing this now is not
370 recommended, since so many sites do look for this. You may get undesirable
371 results by changing this.</P
373 > For instance, different browsers use different encodings of Russian and Czech
374 characters, certain web servers convert pages on-the-fly according to the
375 User Agent header. Giving a <SPAN
379 operating system or browser manufacturer causes some sites in these languages
380 to be garbled; Surfers to Eastern European sites should change it to
381 something closer. And then some page access counters work by looking at the
385 > header; they may fail or break if unavailable. The
386 weather maps of Intellicast have been blocked by their server when no
390 > or cookie is provided, is another example. There are
391 many, many other ways things can go wrong when trying to fool a web server.</P
393 > If you have problems with a site, you will have to adjust your configuration
394 accordingly. Cookies are probably the most likely adjustment that may
395 be required, but by no means the only one.</P
410 speed up web browsing?</A
413 > No, it does not have this ability at all. You want something like
415 HREF="http://www.squid-cache.org/"
418 > for this. And, yes,
419 before you ask, <SPAN
423 with other kinds of proxies like <SPAN
434 >4.10. What about as a firewall? Can <SPAN
440 > Not in the way you mean, or in the way a true firewall can, or a proxy that
441 has this specific capability. <SPAN
445 protect your privacy, but not really protect you from intrusion attempts.</P
456 > logo that replaces ads is very blocky
457 and ugly looking. Can't a better font be used?</A
460 > This is not a font problem. The logo is an image that is created by
464 > on the fly. So as to not waste
465 memory, the image is rather small. The blockiness comes when the
466 image is scaled to fill a largish area. There is not much to be done
467 about this, other than to use one of the other
478 >, or a URL of your choosing.</P
480 >Given the above problem, we have decided to remove the logo option entirely
489 >4.12. I have large empty spaces now where ads used to be.
493 > It would be easy enough to just eliminate this space altogether, rather than
494 fill it with blank space. But, this would create problems with many pages
495 that use the overall size of the ad to help organize the page layout and
496 position the various components of the page where they were intended to be.
497 It is best left this way.</P
508 > filter Secure (HTTPS) URLs?</A
511 > This is a limitation since HTTPS transactions are encrypted SSL sessions
512 between your browser and the secure site, and are meant to be reliably
516 > and private. This means that all cookies and HTTP
517 header information are also encrypted from the time they leave your browser,
518 to the site, and vice versa. <SPAN
522 try to unencrypt this information, so it just passes through as is.
526 > can still catch images and ads that
527 are embedded in the SSL stream though.</P
542 secure is it? Do I need to take any special precautions?</A
545 > There are no known exploits that might effect
549 >. On Unix-like systems,
553 > can run as a non-privileged
554 user, which is how we recommend it be run. Also, by default
558 > only listens to requests
562 >. The server aspect of
566 > is not itself directly exposed to the
567 Internet in this configuration. If you want to have
571 > serve as a LAN proxy, this will have to
572 be opened up to allow for LAN requests. In this case, we'd recommend
573 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main
577 > config file. All LAN hosts can then use
578 this as their proxy address in the browser proxy configuration. In this way,
582 > will not listen on any external ports.
583 Of course, a firewall is always good too. Better safe than sorry.</P
591 >4.15. How can I temporarily disable <SPAN
597 > The easiest way is to access <SPAN
601 browser by using the special URL: <A
606 and select "Toggle Privoxy on or off" from that page. </P
614 >4.16. Where can I find more information about <SPAN
618 and related issues?</A
621 > Other references and sites of interest to <SPAN
635 HREF="http://www.privoxy.org/"
637 >http://www.privoxy.org/</A
658 HREF="http://sourceforge.net/projects/ijbswa"
660 >http://sourceforge.net/projects/ijbswa</A
662 the Project Page for <SPAN
667 HREF="http://sourceforge.net"
693 > from your browser. Alternately,
695 HREF="http://config.privoxy.org"
697 >http://config.privoxy.org</A
699 may work in some situations where the first does not.
719 HREF="javascript:w=Math.floor(screen.width/2);h=Math.floor(screen.height*0.9);void(window.open('http://www.privoxy.org/actions','Feedback','screenx='+w+',width='+w+',height='+h+',scrollbars=yes,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());"
723 >"actions file feedback system"</SPAN
745 HREF="http://www.junkbusters.com/ht/en/cookies.html"
747 >http://www.junkbusters.com/ht/en/cookies.html</A
764 HREF="http://www.waldherr.org/junkbuster/"
766 >http://www.waldherr.org/junkbuster/</A
783 HREF="http://privacy.net/analyze/"
785 >http://privacy.net/analyze/</A
802 HREF="http://www.squid-cache.org/"
804 >http://www.squid-cache.org/</A
830 HREF="configuration.html"